Executives at the financial information company Bloomberg have known about journalists using the company’s terminals to spy on clients at least since September 2011 — more than a year before the practice turned into a scandal that threatens the company’s relationships with its clients.

That month, Erik Schatzker, an anchor at Bloomberg TV and host of “Market Makers,” was reprimanded for making on-air comments about using terminal data to track the activities of at least one story subject, according to two sources with knowledge of the situation.

One source said the matter was a very big deal internally but was handled quietly.

The Bloomberg terminal is the primary source of news for almost every major banker, trader, and financial services employee on Wall Street.

Despite the developing concerns, it's unclear if Bloomberg's terminal business will get impacted materially.